The earliest river-valley civilizations in the Near East arose in Lower Mesopotamia, the alluvial plain of the lower Tigris and Euphrates rivers in present-day central and southern Iraq. The region lies outside the Near East’s “Fertile Crescent” and is one of very low precipitation receiving on average between 4 and 10 inches of rainfall per year. On the other hand, with the development of early irrigation techniques and irrigation canal infrastructure (beginning circa 3,000 B.C.E.), Lower Mesopotamia could be transformed into an extremely productive agricultural environment, as the region’s rivers could provide not only sufficient water for irrigation but also fertile silt to improve the fertility of the soil.